Vitamin D, sometimes referred to as the sunshine vitamin, has once again been linked to improving gastrointestinal (GI) symptoms and quality of life in people with irritable bowel syndrome (IBS).

IBS is a chronic gastrointestinal (GI) condition that affects millions of men, women, and children around the world.

Contrary to popular belief, IBS can involve low-grade inflammation of the GI tissue.

Vitamin D is an established regulator of the immune system and inflammation, and it has shown beneficial effects on a variety of health conditions, including inflammatory bowel disease, fibromyalgia, depression and multiple sclerosis, to name a few.

The most recent study in support of vitamin D supplementation for people with IBS is a randomized double-blind clinical trial, which is the cream of the crop of science experiments.

​Ninety IBS adult patients with a mixture of IBS-constipation, IBS-diarrhea, and IBS-alternating bowel movements were selected for this study. Forty-five were randomly assigned to take 50,000 international units (IU) of vitamin D3 once every two weeks for a period of six months while the other 45 received a placebo.

Participants were required to complete a variety of questionnaires about their symptoms, specifically abdominal pain, flatulence, abdominal distention/bloating, dissatisfaction with bowel habits, and rumbling, as well as their quality of life. They also had to undergo blood work for vitamin D and calcium status. Vitamin D status was assessed by measuring serum 25(OH)D3 levels.

As anticipated, vitamin D levels significantly increased in the group that took the vitamin D supplement. Nearly 70% of the patients in the intervention group began the study with deficient levels (<20 ng/mL 25(OH)D3) but none were deficient after six months.

All IBS symptoms significantly improved in both groups with a significantly higher improvement in the intervention group compared to the placebo group (except dissatisfaction with bowel habits).

An assessment of quality of life produced similar results.

The overall score for quality of life significantly improved in both groups, but greater improvement was seen in the supplemented group.

As far as I know, this is the first clinical trial that has evaluated the effect of vitamin D supplementation on IBS patients but hopefully not the last.

Although future studies are warranted to further support the use of vitamin D to improve IBS symptoms and quality of life, it’s not too early to start talking to your physician about having your vitamin D level tested to see if you might benefit from supplementation or a little extra time in the sun.